1. Field of the Invention
This invention relates generally to structural members, and more particularly to a joining member for mechanically joining a skin to a supporting rib.
2. Description of Related Art
Structural elements for supporting a skin with a rib are known in the art, particularly in the field of aircraft construction, but also in other fields. For example, U.S. Pat. No. 2,218,122 to Scheller et al. describes a structural member for supporting opposing skins of an airplane control element (e.g., wing). The structural member includes one or more web sections riveted between flange scarfs. Each flange scarf includes either a “T”-shaped, two “L”-shaped, or a “U”-shaped rod. Surfaces of the flange scarfs opposite the web sections extend in parallel to the wing covering.
Construction of such structural members is difficult and therefore labor intensive. For example, corresponding holes must be drilled in the central web sections and in the flange scarfs to receive the rivets. For structural integrity, the rivets must fit snugly in the aligned holes. This means the holes must be aligned precisely to receive the rivets. Such precise alignment is difficult to achieve, and takes a substantial amount of time even when possible. Further, structural stresses are concentrated around the rivets.
Other examples of such constructions are shown in Lockshaw et al., U.S. Pat. No. 5,273,806, which teaches a structural element of an aircraft. The structural element includes opposed first and second, laterally and longitudinally extended, generally planar surface structures each having a closed figure pattern of ribbing projecting therefrom toward the opposite surface structure. The ribbing is of respective heights to bridge the space between the surface structures, the opposed ribbing being interlocked in a registered, mating relation. Similar structures are also shown in other Lockshaw patents, including U.S. Pat. Nos. 5,633,053, 5,508,085, 5,273,806, and 5,616,376.
Lockshaw et al., U.S. Pat. No. 5,580,622, teaches a structural element suitable for walls, tanks and bulkhead structures. The structural element includes opposed, axially extended surface structures and ribbing interposed therebetween. The ribbing is integral with one of the surface structures, and fits into a groove that is integral with the other of the surface structures. This arrangement allows the surface structures to be in a freely movable relation responsive to a temporary first relative dimensional condition of the surface structures and ribbing, and in blocking relation against separation of the surface structures responsive to a persistent second relative dimensional condition of the surface structures and ribbing.
The above-described references, incorporated herein by reference, show the use of ribs that are integral with one of the surface structures. The references also teach the engagement of a rib with a groove that is integrally formed in one of the surface structures. However, the prior art does not teach a joining member that is not integral with the surface structure, but is bonded or otherwise attached to the surface structure, and which provides the groove to engage the rib.